Ultimately, maternal comorbidities and pregnancy complications were found to be the strongest predictors of cesarean delivery. Women presenting with preterm labor were significantly less likely to undergo cesarean delivery (OR 0.84, 95% CI 0.73–0.96, risk difference 0.03), which translates to one fewer cesarean delivery for every 35 women presenting with preterm labor. Women presenting with preterm PROM or abruption were more likely to have cesarean deliveries (OR 1.29 95% CI 1.14–1.45, risk difference 0.04, and OR 2.43, 95% CI 2.09–2.81, risk difference 0.15, respectively). Therefore, one additional cesarean delivery was performed for every 25 women presenting with preterm PROM and every 6 women presenting with placental abruption. The strongest predictor of periviable cesarean delivery was PIH. Women with PIH had 15.6 times the odds of cesarean delivery than women without PIH (95% CI 12.3–19.7, risk difference 0.49), suggesting that an additional cesarean delivery was performed for every two women who presented with PIH. Indications for cesarean delivery, including previa, repeat cesarean delivery, and malpresentation placed women at 5 to 6 times the odds of undergoing cesarean delivery, which added a cesarean delivery for every three women presenting with these indications (risk differences 0.30 for previa, 0.33 for repeat cesarean, and 0.31 for malpresentation). Last, women presenting at a gestational age between 24 and 24.6 weeks had more than twice the odds of cesarean delivery compared with women presenting between 23 and 23.6 weeks of gestation (OR 2.14, 95% CI 1.92–2.39, risk difference 0.12), which translates to an additional cesarean delivery for every eight neonates born between 24 and 24.6 weeks. Neither adjusting for delivery hospital nor stratifying the analysis by state changed these findings.
We hypothesized that African American and Hispanic women at periviable gestational ages would be more likely to undergo cesarean delivery. However, neither race, nor any other sociodemographic characteristics, was associated with cesarean delivery. Instead, we found that clinical presentation was the strongest predictor of cesarean delivery.
These findings add to the body of literature that considers the role of race in cesarean decision-making. Previous studies demonstrate racial or ethnic disparities in mode of delivery.1–8 Braveman and colleagues' study of more than 200,000 primiparous women found that African American women were 24% more likely to undergo cesarean delivery than white women, even after controlling for sociodemographic characteristics, insurance status, medical indications, and hospital characteristics.3 Scott-Wright and colleagues examined a cohort of college-educated African American and white women and found that, even with comparable levels of education, African American women had 1.78 times the odds of cesarean delivery than their white counterparts.27 And more recently, Bryant et al studied the delivery experience of more than 28,000 women delivering in a tertiary care center and found that, controlling for known risks, African American women and Hispanic women had 1.48 and 1.19 times the odds of cesarean delivery, respectively.28 These disparities have been found primarily among term deliveries. Our findings suggest that periviable deliveries represent a subset of deliveries wherein race or ethnicity does not predict mode of delivery, but rather, the acuity of the clinical encounter dictates the course of care. For example, preeclampsia, which was the strongest predictor of cesarean delivery, demands prompt delivery for maternal, rather than fetal, benefit when women present with severe forms.
Patient preference has been considered as a potential explanation for racial differences observed in term cesarean delivery rates. Previous work found that among nonpregnant women surveyed about preferences for route of delivery, 21.7% of nonwhite women compared with 7.8% of white women preferred cesarean delivery (P=.03).29 We formulated our hypothesis, in part, on the basis of the premise that patient preference plays a central role in determining mode of delivery when managing periviable deliveries. We assumed that just as African American and Hispanic adults prefer heroic measures and interventional therapies in end-of-life decision-making, they would also prefer to have “everything done” in managing periviable delivery and resuscitative care.30–37 However, our study found that African American and Hispanic women delivering between 23 and 25 weeks of gestation had slightly lower odds of delivering by cesarean delivery compared with white women. This difference was not statistically different from white women. These findings suggest that the option for cesarean delivery may be less subject to patient preference in the periviable window. Patients frequently present with complications that warrant operative intervention independent of parental resuscitation preferences. Although obstetricians report that patient preference should play a role in resuscitation decisions,38 operative decision-making in this context appears to depend most heavily on the clinical presentation. Patient preference is also constrained by the options presented to patients. Obstetricians may not even offer the option of cesarean delivery below a threshold gestational age or under certain clinical scenarios.
As a retrospective cohort study, there are several limitations to the conclusions we can draw from these findings. Owing to the limitations of the data and the variables available in the data set, we are ultimately unable to determine whether the patterns of cesarean delivery observed reflect institutional practice, maternal preference, or physician guidance. We control for hospital effects with a fixed-effects model that revealed no differences in the findings. This suggests that institutional practice may be less of a driving factor. However, we cannot exclude the possibility that paternalism, bias, or perceived patient preference (rather than stated patient preference) on the part of physicians may lead some physicians to be less inclined to provide aggressive care, such as cesarean delivery, for socially disadvantaged women given the expense associated with neonatal intensive care and, potentially, caring for a disabled child. This could serve as an alternative explanation for the reversal in cesarean delivery trends seen in this periviable cohort compared with previous studies. Another limitation of the study is that we identified our predictor and outcome variables by ICD-9-CM codes, not primary chart abstraction. This creates the risk for misclassification. However, this method allows for a large, population-based cohort that is needed to study racial differences in this relatively rare event. Finally, other unmeasured confounders may play a significant role in decision-making and actually account for associations that we observed. However, this is less of a concern with a statistically nonsignificant result.
In conclusion, utilization of cesarean delivery did not differ by race or ethnicity in this cohort of periviable deliveries. Although the utility of performing cesarean deliveries for fetal benefit at periviable gestational ages remains in question, our findings highlight that cesarean delivery is frequently performed when clinical acuity or maternal benefit warrants prompt intervention. The findings of this study point to the complexity of clinical decision-making and to the need for greater understanding of how social and clinical factors are weighed and prioritized in cesarean decision-making.
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“Outpatient” or “intrauterine” fetal deaths were designated by the following International Classification of Diseases, 9th Revision, Clinical Modification codes using criteria described by Phibbs et al in previous work.15 Fetal deaths with these diagnoses were excluded from the analysis:
Papyraceous fetus: 646.01
Intrauterine death: 656.40, -41, or -43
Decreased fetal movement: 655.71
Cord entanglement with compression: 663.20
Cord entanglement without compression: 663.31
Ruptured uterus before delivery: 665.01
Insertion of laminaria: 69.93
Hysterotomy to terminate pregnancy: 74.91
The following International Classification of Diseases, 9th Revision, Clinical Modification codes were used to designate maternal and fetal characteristics included as covariates in the models:
Preexisting diabetes mellitus: 250.xx, 648.0x, 357.2, 362.0, 362.01, 362.02, 366.41
Gestational diabetes: 648.8x
Chronic hypertension: 642.0x, 642.1x, 642.2x
Pregnancy-induced hypertension: 642.4x, 642.5x, 642.7x
Preterm labor: 644.0x, 644.2x
Preterm premature rupture of membranes: 658.1x, 658.2x
Placental abruption: 641.2x
Repeat cesarean: 654.2x and birth certificate indicator
Placenta previa: 641.0x, 641.1x